QCS 2014 Section 06: Road Works Page 1

Part 06: Concrete Road Pavements

6 CONCRETE ROAD PAVEMENTS .......................................................................... 3

6.1 GENERAL REQUIREMENTS .................................................................................. 3
6.1.1 Scope 3
6.1.2 References 3
6.1.3 Quality Control of Concrete Strength 4
6.2 TRIAL LENGTH ....................................................................................................... 5
6.2.1 General Requirements for Trial Length 5
6.2.2 Assessment of Trial Length 6
6.2.3 Approval and Acceptance of Trial Length 7
6.3 REQUIREMENTS FOR PAVEMENT QUALITY CONCRETE .................................. 7
6.3.1 Materials and Mix Designs for Pavement Quality Concrete 7
6.3.2 Workability of Pavement Quality Concrete 7
6.3.3 Trial Mixes 8
6.3.4 Separation Membrane 8
6.3.5 General Requirements for Steel Reinforcement 8

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6.3.6 Jointed Reinforced Concrete Slabs 9
6.3.7 Continuously Reinforced Concrete Slabs (CRCP or CRCR) 10
6.3.8 General Requirements for Transverse Joints hl 10
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6.3.9 Transverse Contraction Joints 11
6.3.10 Transverse Expansion Joints 11
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6.3.11 Transverse Warping Joints 11

6.3.12 Transverse Construction Joints 11
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6.3.13 General Requirements for Longitudinal Joints 12

6.3.14 Longitudinal Construction Joints 13
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6.3.15 Dowel Bars 13

6.3.16 Joint Grooves 16
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6.3.17 Groove Formers and Bottom Crack Inducers 17

6.3.18 Joint Filler Board 18
6.3.19 Preparation and Sealing of Joint Grooves 18
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6.3.20 Sealing with Applied Sealants 19

6.3.21 Sealing with Compression Seals 20
6.3.22 Joint Seals 21
6.3.23 Joints at Manhole and Gully Slabs 21
6.3.24 Inspection of Dowel Bars 22
6.3.25 Side Forms, Rails and Guide Wires 22
6.3.26 Delivery, Storage and Batching of Concreting Materials 23
6.3.27 Mixing Concrete 24
6.3.28 Transport and Delivery 24
6.3.29 General Requirements for Construction by Machine 24
6.3.30 Construction by Fixed Form Paving Machines 25
6.3.31 Construction by Slip-Form Paving Machine 26
6.3.32 Construction by Small Paving Machines or Hand Guided Methods 26
6.3.33 Surface Textures 28
6.3.34 Strength 29
6.3.35 Trial Mixes 29
6.3.36 Trial Length 29
QCS 2014 Section 06: Road Works Page 2
Part 06: Concrete Road Pavements

6.3.37 Surface Finish 30

6.4 REQUIREMENTS FOR CEMENT BOUND MATERIALS ....................................... 30
6.4.1 General Requirements for Cement Bound Materials 30
6.4.2 Batching and Mixing 31
6.4.3 Transporting 31
6.4.4 Laying 31
6.4.5 Compacting 32
6.4.6 Curing 32
6.4.7 Preliminary Trial 33
6.4.8 Cement Bound Material Category 1 (CBM1) 33
6.4.9 Cement Bound Material Category 2 (CBM2) 34
6.4.10 Cement Bound Material Category 3 (CBM3) 34
6.4.11 Cement Bound Material Category 4 (CBM4) 34
6.4.12 Testing of Cement Bound Materials 35
6.4.13 Special Requirements for Cement Bound Materials 35

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QCS 2014 Section 06: Road Works Page 3
Part 06: Concrete Road Pavements

6 CONCRETE ROAD PAVEMENTS

6.1 GENERAL REQUIREMENTS

6.1.1 Scope

1 This part of the specification covers the; materials, mix designs, production and laying of
pavement quality concrete, lean mix concrete and cement bound materials.

2 Related Sections and Parts are:

This Section
Part 3 ............... Earthworks
Part 4 ............... Unbound Pavement Materials
Part 5 ............... Asphalt Works

Section 5 - Concrete

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Part 16 ............ Miscellaneous - Pavement Quality Concrete

6.1.2 References
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1 The following standards are referred to in this part of the specification
BS 1377: Part 9 ..........Methods of testing soils – in-situ tests
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BS 1881...................... Methods of testing concrete -

BS 1924: Part 1 & 2.... Stabilised materials for civil engineering purposes
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BS 2499 & BS EN 14188 Hot applied joint sealants for road pavements
BS 2752...................... Chloroprene rubber compounds
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BS 3900: Part F12 ...... Determination of resistance to neutral salt spray

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BS 3963...................... Method for testing the performance of concrete mixers

BS EN ISO 11600 ...... Two part polysulphide sealants
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BS 4449...................... Reinforcing bars

BS 4482...................... Cold drawn steel wire for reinforcing concrete
BS 4483...................... Reinforcing mesh
BS 5212: Part 1 & 2.... Cold applied joint sealants for concrete pavements
BS EN 206 & BS 8500 Supply of concrete
BS 7542...................... Methods for test of curing compounds for concrete
BS 812........................ Testing methods for aggregates

ASTM D3406 .............. Specification for joint sealant - hot applied elastomeric types
ASTM 7116 ................ Specification for joint sealant - hot applied elastomeric types (jet
fuel resistant)
ASTM D2628-91......... Specification for preformed joint seals

DTP ............................ Manual of contract documents for highway works -Volume 1

specification for highway works
QCS 2014 Section 06: Road Works Page 4
Part 06: Concrete Road Pavements

6.1.3 Quality Control of Concrete Strength

1 Sampling and testing for, and compliance with the specified characteristics strength of
designed mixes shall be in accordance with BS EN 206 & BS 8500, except that it shall be at
the following rates of sampling and testing and meet the following requirements:

(a) Concrete cubes of the appropriate size shall be made, cured and tested in accordance
with BS 1881 respectively from concrete delivered to the paving plant, each group
being from a different delivery of concrete. At least 3 cubes shall be made per group
2
for each 600 m of concrete slab and not less than 6 groups shall be made each day,
2
for each type of mix. For areas less than 600 m , at least 4 cubes shall be made for
2
each 100 m or less. This rate of sampling and testing may be reduced at the
Engineer's discretion.
2
(b) For areas of 600 m or more, one cube shall be tested in compression at 7 days and
the other two at 28 days after mixing. Groups of four consecutive results at 28 days
shall be used for assessing the strength for compliance with BS EN 206 & BS 8500.

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For areas less than 600 m , two cubes shall be tested at 7 days and two tested at 28
days and assessed in accordance with BS EN 206 & BS 8500.
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The ratio R between 7 and 28 day strengths shall be established for the mix to be used
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in the slab by testing pairs of cubes at each age on at least six batches of the
proposed mix or it shall be quoted by the supplier of the concrete. The average
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strength of the 7 day pair of cubes shall be divided by the average strength of the 28-
day pair of cubes for each batch and the ratio R shall be the average of these six
values. The ratio R shall be expressed to three decimal places.
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(d) If during the construction of the trial length or during normal working, the average value
of any 4 consecutive 7 day test results falls below the strengths required then the
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cement content of the concrete shall be increased by 5 % by mass or by an amount

agreed by the Engineer. The increased cement content shall be maintained at least
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until the four corresponding 28-day tests have been assessed. If the cement content is
increased, the concrete mix shall be adjusted to maintain the required workability.
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(e) The values in columns 3 and 4 of Table 6.1 may only be used with the permission of
the Engineer when sufficient test results on trial mixes for calculating the ratio are not
available. Once sufficient results are available from normal working the ratio R shall be
calculated from the results available on Site.
(f) To assess the time for use of a concrete slab by traffic, the strength development rate
may be predetermined by trial mixes. Alternatively pairs of cubes shall be made for
2
each 600 m or less and stored alongside the pavement in containers or in such a way
that their sides are well insulated. If thermal insulation is used for accelerated curing
the cubes shall be similarly insulated. Pairs of cubes shall be tested at intervals
decided by the Engineer. Tests for compliance with the specified strength shall be
made in the normal way.
QCS 2014 Section 06: Road Works Page 5
Part 06: Concrete Road Pavements

Table 6.1
7 Day Cube Strength

All Mixes, R PC Mixes, R not PFA or ggbs mixes, R

Grade of Concrete 2
available available not available N/mm

C40 43R 35 29
C30 33R 27 22
C20 22R 18 14
C15 17R 13 11
C10 10R 8 7
C7.5 7R 5.5 4.5

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6.2 TRIAL LENGTH

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6.2.1 General Requirements for Trial Length
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1 Except in rapid construction projects, at least one month prior to the construction of the trial
length of surface slabs or CRCR (Continuously Reinforced Concrete Road Base) the
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Contractor shall submit for the Engineer's approval a detailed description of the proposed
materials, mix proportions, plant, equipment and construction methods.
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2 No trials of new materials, plants, equipment or construction methods; nor any development
of them shall be permitted either during the construction of the trial length or in any
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subsequent paving work, unless they form part of further approved trials.
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3 The Contractor shall demonstrate the materials, mix proportions, plant, equipment and
method of construction that are proposed for concrete paving, by first constructing a trial
length of slab, at least 150m but not more than 300 m, long for mechanised construction, and
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at least 30m long for hand guided methods, or otherwise as directed by the Engineer.

4 The mix proportions decided by trial mixes may be adjusted during the trial but shall not be
changed once the trial length has been approved except with the agreement of the Engineer.

5 The trial length shall be constructed in two parts over a period comprising at least part of two
separate working days, with a minimum of half the proposed trial lengths constructed each
day. The trial length shall be constructed at a similar rate to that which is proposed for the
main construction in the permanent works.

6 At least two transverse joints and one longitudinal joint of each type that are proposed for
unreinforced concrete slabs and jointed reinforced concrete slabs in the main construction in
the permanent works shall be constructed and assessed in the trial length.

7 If in the trial length expansion joints are not demonstrated, the first 2 expansion joints and at
least the first 150 m of longitudinal construction joint for mechanised paving, or 30 m for hand
guided method of construction laid in the main construction in the permanent works, shall be
considered the trial length for these joints.
QCS 2014 Section 06: Road Works Page 6
Part 06: Concrete Road Pavements

8 One construction joint shall be demonstrated in each trial length of CRCP or CRCR.

6.2.2 Assessment of Trial Length

1 The trial length shall comply with the Specification in all respects, with the following additions
and exceptions provided in (a) through (d) below.

(a) Surface Levels and irregularity

(i) in checking for compliance the levels shall be taken at intervals of not more than
2.5 m along any line or lines parallel to the longitudinal centre line of the trial
length.
(ii) The maximum number of permitted irregularities of pavement surfaces shall
comply with the requirements for asphalt pavements as per Part 5
for 300 m lengths. Shorter trial lengths shall be assessed pro-rata based on
values for a 300 m length.

(b) Joints

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(i) At least 3 cores of minimum diameter 100 mm shall be taken from the slab at
joints to check the lateral and vertical location of joint grooves and bottom crack
inducers. hl
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(ii) After a minimum of 24 hours following construction the removable part of the
joint groove former shall be taken out and at least three joints and the sides of
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the groove shall be inspected for compaction. If there are voids the size and
number should be compared with a similar size section of the photograph for 3%
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excess voidage in BS 1881. If there is excess voidage, additional

compaction shall be provided and further joints inspected. The joints so
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exposed shall be temporarily or permanently sealed

(iii) Alignment of dowel bars shall be inspected in any two consecutive transverse
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joints. If the position or alignment of the dowel bars at one of these joints does
not comply after the next 3 consecutive joints of the same type have been
inspected then the method of placing dowels shall be deemed to be satisfactory.
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(iv) If there are deficiencies in the first expansion joint constructed as a trial,
the next expansion joint shall be a trial joint. Should this also be deficient further
trial expansion joints shall be made as part of a trial length which shall not form
part of the Permanent Works, unless agreed by the Engineer.
(c) Density
(i) Density shall be assessed from at least 3 cores drilled from each part of the trial
length.
(d) Position of Reinforcement and Tie Bars
(i) Compliance for the position of steel reinforcement and for the position and
alignment of tie bars shall be checked by drilling additional cores from the slab
unless they can be determined from cores taken for density assessment.
QCS 2014 Section 06: Road Works Page 7
Part 06: Concrete Road Pavements

6.2.3 Approval and Acceptance of Trial Length

1 Approval of the materials, mix proportions, plant, equipment and construction methods will be
given when a trial length complies with the specifications. The Contractor shall not proceed
with normal working until the trial length has been approved and any earlier defective trial
lengths have been removed, unless they can be remedied to the satisfaction of the Engineer.

2 When approval has been given, the materials, mix proportions, plant, equipment and
construction methods shall not thereafter be changed, without the approval of the Engineer
except for maintenance of plant. Any changes in materials, mix proportions, plant,
equipment, and construction methods shall entitle the Engineer to require the Contractor to
lay a further trial length as described in this Clause to demonstrate that these changes will
not adversely affect the permanent works.

3 Trial lengths which do not comply with the Specification, with the exception of areas within
the pavement surface which can be remedied shall be removed immediately upon notification
of deficiencies by the Engineer and the Contractor shall construct a further trial length.

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6.3 REQUIREMENTS FOR PAVEMENT QUALITY CONCRETE

6.3.1 hl
Materials and Mix Designs for Pavement Quality Concrete
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1 The constituent materials and mix designs for pavement quality control shall be as per
Section 5: Part 16.
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6.3.2 Workability of Pavement Quality Concrete

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1 The workability of the concrete at the point of placing shall enable the concrete to be fully
compacted and finished without undue flow. The optimum workability for the mix to suit the
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paving plant being used shall be determined by the Contractor and approved by the
Engineer.
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2 The workability shall be determined by the compacting factor test, or the Vebe test or
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alternatively for concrete grade C20 or below, by the slump test, all in accordance with BS
1881, at the minimum rate of one determination per 300 m2 of slab laid or 6 times per day,
whichever is greater. For areas less than 300 m2 the rate shall be at least one determination
to each 20 m length of slab or at least 3 times per day.

3 Alternatively the volumetric method of determining the Compacting Factor in BS 1881 may be
used. Tests for workability shall be carried out at the point of placing, in conjunction with
tests for strength and any tests for air content. The workability shall be maintained at the
optimum within the following tolerances.
Compacting Factor (CF) +0.03
Slump +20mm
Vebe +3 seconds or as agreed by the Engineer as a results of trial
mixes.
4 Any alteration to the optimum workability necessitated by a change in conditions shall be
agreed beforehand by the Engineer.
QCS 2014 Section 06: Road Works Page 8
Part 06: Concrete Road Pavements

5 If any determination of workability gives result outside the tolerance, a further test shall be
made immediately on the next available load of concrete. The average of the two consecutive
results and the difference between them shall be calculated. If the average is not within the
tolerance or the difference is greater than 0.06 for CF or 20 mm for slump, or 6 seconds for
Vebe or other value agreed with the Engineer, subsequent samples shall be taken from the
delivery vehicles, which shall not be allowed to discharge into the Works until compliance
with the Specification has been established.

6.3.3 Trial Mixes

1 For concrete grades C15 and above the Contractor shall carry out laboratory trials of
designed mixes with the materials from all sources to be used in the Works, in accordance
with BS EN 206 & BS 8500 unless recent data relating entirely to the proposed mix is
approved by the Engineer.

2 The trial mixes shall be repeated if necessary until the proportions of ingredients are
determined which will produce a concrete which complies in all respects with the

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Specification.

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3 Apart from minor adjustments to the mix as permitted by BS EN 206 & BS 8500 any changes
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in sources of materials or mix proportions that are proposed by the Contractor during the
course of the Works shall be assessed by making laboratory trial mixes and the construction
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of a further trial length unless otherwise approval is given by the Engineer.
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6.3.4 Separation Membrane

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1 A separation membrane shall be used between jointed reinforced concrete surface slabs or
unreinforced concrete surface slabs and the sub base.
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2 Separation membranes shall be impermeable plastic sheeting 125 microns thick laid flat
without creases. Where an overlap of plastic sheets is necessary, this shall be at least
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300 mm. There shall be no standing water on or under the membrane when the concrete is
placed upon it.
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3 Under CRCP and CRCR a waterproof membrane shall be provided, which shall be a
bituminous spray before concreting. Where a bituminous spray has been used to cure
cement bound material or wet lean concrete then only those areas which have been
damaged shall be resprayed after making good. The waterproof membrane shall be
bituminous cutback in accordance with clause 5.12 of this Section.

6.3.5 General Requirements for Steel Reinforcement

1 Reinforcement shall comply with any of the following standards and be in prefabricated
sheets or cages, or bars assembled on site and shall be free from oil, dirt, loose rust and
scale:

(a) (Carbon steel bars for the reinforcement of concrete) BS 4449

(b) (Cold-reduced steel wire for the reinforcement of concrete) BS 4482
(c) (Steel fabric for the reinforcement of concrete) BS 4483
QCS 2014 Section 06: Road Works Page 9
Part 06: Concrete Road Pavements

(d) When deformed bars are used they shall conform to Type 2 bond classification of BS
4449.

2 Spacing of bars shall not be less than twice the maximum size of aggregate used. Laps in
longitudinal bars shall be not less than 35 times bar diameters or 450 mm which ever is
greater. In continuously reinforced concrete slabs (CRCP or CRCR) only one third of the
laps may be in any one transverse section, except in single bay width construction where half
the laps may be in any one transverse section. There shall be a minimum of 1.2 m
longitudinally between groups of transverse laps or laps in prefabricated reinforcement
sheets. Alternatively the reinforcement may be butt welded by a process approved by the
Engineer.

3 Laps in a transverse reinforcement shall be a minimum of 300 mm. Where prefabricated

reinforcement sheets are used and longitudinal and transverse laps would coincide, no lap is
required in the transverse bars within the lap of the longitudinal reinforcement. These
transverse bars may be cropped or fabricated shorter so that the requirements for cover are
met.

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4 If the reinforcement is positioned prior to concreting, it shall be fixed on approved metal
supports and retained in position at the required depth below the finished surface and
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distance from the edge of the slab so as to ensure that the required cover is achieved.
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Reinforcement assembled on site shall be tied, or firmly fixed, by a procedure agreed with the
Engineer, at sufficient intersections to provide sufficient rigidity to ensure that the
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reinforcement remains in the correct position during construction of the slab.

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5 Alternatively, when a reinforced concrete slab (JRC, CRCP or CRCR) is constructed in two
layers, the reinforcement in the form of prefabricated sheets may be placed on or into the
bottom layer which shall be spread and compacted to such a level that it will support the
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reinforcement without distortion at the required position in the slab. The sheets shall be tied
together at overlaps and after the second layer has been spread and compacted, the
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reinforcement shall have the required cover.

6 When a reinforced concrete slab is constructed at maximum width the transverse

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reinforcement in the centre of each slab width shall be a minimum of 12 mm nominal

diameter bars at 600 mm centres. This reinforcement shall be at least 600 mm longer than
one third of the width of the slab and be lapped to other transverse reinforcement bars or
sheets, or be continuous across the whole width of each slab.

6.3.6 Jointed Reinforced Concrete Slabs

1 The reinforcement shall be so placed that after compaction of the concrete, the cover below
the finished surface of the slab is 50 + 10 mm for slabs less than 200 mm thick, 60 + 10 mm
for slabs 200 mm or more but less than 270 mm thick and 70+20 mm for slabs 270 mm thick
or more.

2 The negative vertical tolerance shall not be permitted beneath road stud recesses.

3 Where traffic signal detector loops are to be installed, the minimum cover to the
reinforcement from the surface shall be 100 mm.
QCS 2014 Section 06: Road Works Page 10
Part 06: Concrete Road Pavements

4 The vertical cover between any longitudinal joint groove forming strip and any reinforcement
or tie bars shall be at a minimum of 30 mm.

5 Any transverse bars shall be at right angles to the longitudinal axis of the carriageway. Any
transverse reinforcement shall terminate at 125+25 mm from the edges of the slab and
longitudinal joints, where tie bars are used.

6 No longitudinal bars shall lie within 100 mm of a longitudinal joint. The reinforcement shall
terminate 300 mm + 50 mm from any transverse joint, excluding emergency construction
joints.

6.3.7 Continuously Reinforced Concrete Slabs (CRCP or CRCR)

1 The reinforcement shall be Grade 460 deformed steel bars as detailed on the Contract
Drawings.

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2 The reinforcement shall consists of bars assembled on site, or of prefabricated sheets.

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3 Except where otherwise shown on the Drawings the longitudinal bars shall be parallel to the
centre line of the road. hl
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4 The reinforcement shall be positioned so that, after compaction of the concrete, it shall be at
the mid depth of the specified thickness of the slab + 25 mm. No longitudinal bar shall lie
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within 100mm of a longitudinal joint.

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5 In reinforcement assembled on site, longitudinal bars shall be placed immediately above any
transverse bars, which shall be at right angles to the longitudinal axis of the carriageway.
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Any transverse reinforcement shall terminate 125+25 mm from the edges of the slab and
longitudinal joints where tie bars are used.
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6.3.8 General Requirements for Transverse Joints

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1 Transverse joints shall be provided in unreinforced and jointed reinforced concrete slabs and
shall be contraction, expansion or warping joints at the spacing shown on the Drawings such
that for unreinforced concrete slabs the length/width ratio shall be not greater than 2.0.

2 Joints in the surface slab and sub-base shall be staggered so that they are not coincident
vertically and are at least 1m apart.

3 Transverse joints shall be straight within the following tolerances along the intended line of
the joint, which is the straight line transverse to the longitudinal axis of the carriageway at the
position proposed by the Contractor and agreed by the Engineer, except at road junctions or
roundabouts where the positions shall be as shown on the Drawings:

(a) Deviations of the filler board or bottom crack inducer from the intended line of the
joint shall be not greater than ± 10 mm.

(b) The best fit straight line through the joint groove as constructed shall be not more
than 25 mm from the intended line of the joint.

(c) Deviations of the joint groove from the best fit straight line of the joint shall be not
greater than 10 mm.
QCS 2014 Section 06: Road Works Page 11
Part 06: Concrete Road Pavements

(d) When top groove formers and bottom crack inducers are used, the joint groove
as constructed shall be located vertically above the bottom crack inducer within a
horizontal tolerance of ± 25 mm.

4 Transverse joints on each side of a longitudinal joint shall be in line with each other and of
the same type and width. The position of the joints relative to manholes and gullies shall be in
accordance with the Drawings.

5 Transverse joints shall have a sealing groove which shall be sealed in compliance with
Clause 6.3.20 of the specification.

6.3.9 Transverse Contraction Joints

1 Contraction joints shall consist of:

(a) Either a sawn joint groove, or

(b) a wet formed joint groove and a bottom crack inducer

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(c) dowel bars
(d) a sealing groove.

6.3.10 Transverse Expansion Joints

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1 Expansion joints shall consist of:
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(a) a joint filler board

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(b) dowel bars

(c) a sealing groove.
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2 The filler board shall be positioned vertically within the prefabricated joint assemblies along
the line of the joint and at such depth below the surface as will not impede the passage of the
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finishing beams on the paving machines.

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3 The joint filler board together with the sealing groove shall provide a complete separation of
adjacent slabs and any spaces around dowel bars and between the sub-base and the filler
board shall be packed with a suitable compressible material after fixing the joint assembly.

6.3.11 Transverse Warping Joints

1 Warping joints shall consist of:

(a) Either a sawn joint groove, or

(b) a wet formed joint groove and a bottom crack inducer
(c) tie bars
(d) a sealing groove.

6.3.12 Transverse Construction Joints

1 Construction joints made at the end of a working day in unreinforced concrete slabs and
jointed reinforced concrete slabs shall be expansion joints or contraction joints. In the event
of mechanical breakdown of the concreting machinery, or at the onset of adverse weather,
emergency joints may be formed.
QCS 2014 Section 06: Road Works Page 12
Part 06: Concrete Road Pavements

2 Emergency joints in unreinforced concrete slabs shall be either contraction or expansion

joints not less than 2.5 m from the preceding or succeeding joint position.

3 Emergency joints in jointed reinforced concrete slabs shall be not less than 2.5 m from the
preceding or succeeding joint position. The stop end formwork shall be sufficiently rigid to
ensure that dowel bars, tie bars or reinforcement will be held in position in compliance with
the specification, and placed in such a position that it permits the longitudinal reinforcement
to project through the joint for a distance of at least 750 mm.

4 Construction joints in continuously reinforced concrete slabs (CRCP and CRCR) in an

emergency shall not be constructed within 1.5 m of any lap in the longitudinal reinforcement
without the approval of the Engineer. The stop end formwork shall be sufficiently rigid to
ensure that the longitudinal reinforcement and the tie bars projecting through the joint are
held in the correct position.

6.3.13 General Requirements for Longitudinal Joints

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1 Longitudinal joints shall be provided in surface slabs between or at the centre of traffic lanes
within the allowable positions as shown on the Drawings, so that bay widths are not greater
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than 4.2 m (or 5.0 m with limestone aggregate) for unreinforced slabs, or 6 m (or 7.6 m with
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limestone aggregate) for reinforced concrete surface slabs with transverse reinforcement.
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2 Longitudinal joints shall be provided in CRCR between lanes or at the centre of lanes, within
a tolerance of +150 mm so that bay widths are not greater than 6 m (or 7.6 m with limestone
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aggregate).

3 Joints in the surface slab, road base or sub-base shall be staggered so that they are not
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coincident vertically and are least 300 mm apart. The positions of all longitudinal joints in any
slab shall be agreed by the Engineer prior to construction of the slab.
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4 Wet-formed longitudinal joints shall consists of wet-formed joint grooves, bottom crack
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inducer and tie bars except where transverse reinforcement is permitted in lieu.

5 Longitudinal joints shall be constructed in the positions agreed by the Engineer within the
following tolerances:

(a) Deviations of the bottom crack inducer from the intended line of the joint parallel
to the axis of the road shall not be greater than +13 m.

(b) The joint groove shall be located vertically above the bottom crack inducers within
a horizontal tolerances of +25 mm.

(c) The best fit line along the constructed joint groove, shall be not more than 25 mm
from the intended line of the joint.
(d) Deviations of the joint groove from the best fit line of the joint shall be not greater
than 10 mm.
QCS 2014 Section 06: Road Works Page 13
Part 06: Concrete Road Pavements

6 Tie bars may be replaced by continuous transverse reinforcement across the joints in
continuously reinforced concrete slabs, which are constructed in more than one lane width in
one operation, provided that the transverse reinforcement is a minimum of 12 mm diameter
bars at 600 mm centres.

6.3.14 Longitudinal Construction Joints

1 Longitudinal construction joints between separate slabs shall have tie bars with a joint
groove. Alternatively, if split forms are used, the transverse reinforcement, if 12 mm diameter
or more, may be continued across the joint for a minimum of 500 mm or 30 times the
diameter of the transverse reinforcement bars, whichever is greater.

2 A joint sealing groove is not required in construction joints in continuously reinforced concrete
road bases. Where the edge of the concrete slab is damaged it shall be made good to the
approval of the Engineer before the adjacent slab is constructed.

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6.3.15 Dowel Bars

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1 Dowel bars shall be Grade 250 steel complying with BS 4449 and shall be free from oil, dirt,
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loose rust and scale. They shall be straight, free of burrs and other irregularities and the
sliding ends sawn or, if approved by the Engineer, cropped cleanly with no protrusions
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outside the normal diameter of the bar. For expansion joints, dowel bars shall be 25mm
diameter at 300 mm spacing, 600 mm long for slabs up to 239 mm thick and 32 mm diameter
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for slabs 240 mm thick or more. For contraction joints, dowels shall be 20 mm diameter at
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300 mm spacing 400 mm long for slabs up to 239 mm thick and 25 mm diameter for slabs
240 mm thick or more.
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2 Dowel bars shall be supported on cradles in prefabricated joint assemblies positioned prior to
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construction of the slab. For contraction joints, as an alternative to prefabricated assemblies,

dowel bars may be mechanically inserted with vibration into the concrete by a method which
shall ensure full recompaction of the concrete around the dowel bars and the surface finished
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by a diagonal finishing beam. Or a longitudinal oscillating float travelling across the slab.

3 Dowel bars shall be positioned at mid-depth from the surface level of the slab ± 20 mm.
They shall be aligned parallel to the finished surface of the slab, to the centre line of the
carriageway and to each other within the following tolerances:

(a) for bars supported on cradles prior to construction of the slab and for inserted
bars in two layers construction prior to placing the top layer:
(i) All bars in a joint shall be within ± 3 mm per 300 mm length of bars.
(ii) Two thirds of the bars shall be within ± 2 mm per 300 mm length of bar.

(iii) No bar shall differ in alignment from an adjoining bar by more than 3 mm per
300 mm length of bar in either the horizontal or vertical plane.

(b) for all bars, after construction of the slab:

(i) Twice the tolerances for alignment as in (i) above.
QCS 2014 Section 06: Road Works Page 14
Part 06: Concrete Road Pavements

(ii) Equally positioned about the intended line of the joint within a tolerance of ± 25
mm.

4 Cradles supporting dowel bars shall not extend across the line of the joint.

5 Dowel bars, supported on cradles in assemblies, when subjected to a load of 110N applied at
either end and in either the vertical or horizontal direction (upwards and downwards and both
directions horizontally) shall not deflect more than the following limits:

6 Two thirds of the number of bars of any assembly tested shall not deflect more than 2 mm
per 300 mm length of bar.

7 The remainder of the bars in that assembly shall not deflect more than 3 mm per 300 mm
length of bar.

8 The assembly of dowel bars and supporting cradles, including the joint filler board in the case
of expansion joints shall have the following degree of rigidity when fixed in position:

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9 For expansion joints the deflection of the top edge of the filler board shall be not
greater than 13 mm, when a load of 1.3 kN is applied perpendicular to the vertical
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face of the joint filler board and distributed over a length of 600 mm by means of
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a bar or timber packing at mid depth and midway between individual fixings, or
300 mm from either end of any length of filler board, if a continuous fixing is used.
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The residual deflection after removal of the load shall be not more than 3 mm.
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10 The joint assembly fixings to the sub-base shall not fail under the 1.3kN load
applied for testing the rigidity of the assembly but shall fail before the load
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reaches 2.6 kN.

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11 The fixings for contraction joints shall not fail under a 1.3 kN load and shall fail
before the load reaches 2.6 kN when applied over a length of 600 mm by means
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of a bar or timber packing placed as near to the level of the line of fixings as
practicable.

12 Failure of the fixings shall be deemed to be when there is displacement of the

assemblies by more than 3 mm with any form of fixing, under the test load. The
displacement shall be measured at the nearest part of the assembly to the centre
of the bar or timber packing.

13 Dowel bars shall be covered by a thin plastic sheath over the whole length of the bar. The
sheath shall be tough, durable and of an average thickness not greater than 1.25 mm. The
sheathed bar shall comply with the following pull out test:
QCS 2014 Section 06: Road Works Page 15
Part 06: Concrete Road Pavements

14 Four bars shall be taken at random from stock and without any special
preparation shall be covered by sheaths. The dowel bars which have been
sheathed shall be cast centrally into concrete specimens 150x150x450 mm,
made of the same mix proportions to be used in the pavement, but with a
maximum nominal aggregate size of 20 mm and cured in accordance with
BS 1881. At 7 days a tensile load shall be applied to achieve a movement
of the bar at least 0.25 mm. The average bond stress to achieve this movement
shall be not greater than 0.14 N/mm2.

15 For expansion joints a closely fitting cap 100 mm long consisting of waterproofed cardboard
or an approved synthetic material shall be placed over one end of each
dowel bar. An expansion space 10 mm greater than the thickness of the joint filler board shall
be formed between the end of the cap and the end of the dowel bar.

16 Tie Bars

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17 Tie bars in transverse or longitudinal joints shall be Grade 250 steel or Grade 460 deformed

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steel bars complying with BS 4449, in accordance with the requirements given below and
Table 6.2. Deformed bars shall have Type 2 bond classification. Tie bars shall be free from
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oil, dirt, loose rust and scale. Tie bars which are to be cranked and later straightened shall be
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Grade 250.
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18 Tie bars projecting across a longitudinal joint shall be protected from corrosion by a flexible
polymeric corrosion resistant coating, bonded onto the previously cleaned centre section,
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leaving between 250 mm and 300 mm of each of the bars uncoated.

19 Where tie bars are cranked for construction joints and later straightened the coating shall be
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shown to be capable of being straightened through 90 degrees without cracking. The coating
shall also be able to withstand 250 hours immersion in a salt fog cabinet complying with BS
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3900 : Part F12, without showing any visible cracking, or corrosion of the protected part of
the bar. Any damage observed on the coating after straightening shall be made good before
the concrete is placed.
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20 Tie bars in warping joints and wet-formed longitudinal joints shall be made up into rigid
assemblies with adequate supports and fixings to remain firmly in position during the
construction of the slab.

21 Alternatively, tie bars at longitudinal joints may be mechanically inserted by vibration from
above using a method which ensures recompaction of the concrete around the tie bars.

22 At longitudinal construction joints, tie bars may be adequately fixed to side forms or inserted
into the side of the slab by a method which ensures recompaction of the concrete around the
tie bars and adequate bond and which shall be approved by the Engineer.

23 Tie bars shall be positioned and remain within the middle third of the slab depth,
approximately parallel to the surface and approximately perpendicular to the line of the joint,
with the centre of each bar on the intended line of the joints within a tolerance of ± 50 mm,
and with a minimum cover of 30 mm below any top crack inducer or joint groove for slabs
200 mm thick or more, or 20 mm for slabs up to 200 mm thick.
QCS 2014 Section 06: Road Works Page 16
Part 06: Concrete Road Pavements

24 At transverse construction joints in continuously reinforced concrete, tie bars shall be 1.5 m
long and of the same grade and size as the longitudinal reinforcement, and shall be fixed at
twice the normal spacing midway between the longitudinal reinforcement bars so that
750 mm ± 50 mm extends each side of the joint at the same level as the longitudinal
reinforcement and be tied to the transverse reinforcement. Where paving from a construction
joint is not resumed within 5 days, and extra longitudinal reinforcement bar at 8 m long shall
be lapped and tied to each tie bar. These extra bars may be combined with the tie bars.
Where the spacing between longitudinal reinforcement and the extra 8 m long bars is less
than 90 mm, the nominal size of aggregate shall be 20 mm for a sufficient number of
concrete batches to complete that section of pavement.

25 Where tie bars are used in longitudinal joints in continuously reinforced concrete they shall be
placed at the same level as the transverse reinforcement and tied to the longitudinal
reinforcement.

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Table 6.2

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Tie Bar Details

Joints Diameter (mm)

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Grade of Steel Length (mm) Spacing (mm)
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Transverse Twice the
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construction joints As for main spacing of

460 1500
in continuously reinforcement main
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reinforced concrete reinforcement

Emergency
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construction joints
in jointed reinforced
250 or 1000 600
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concrete slabs 12
460 deformed 750 600
other than at
contraction or
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expansion joints
250 or 1000 300
Warping joints 12
460 deformed 750 600
Longitudinal.
All joints, except
250 or 1000 600
where transverse 12
460 deformed 750 600
reinforcement is
permitted in lieu

Note: The transverse reinforcement may be continued across the joint in reinforced concrete
with the approval of the Engineer if the bars are of a minimum nominal diameter of
12 mm and the bars are protected from corrosion and the cover is as required in this
Clause.
6.3.16 Joint Grooves

1 Transverse contraction or warping joint grooves shall be sawn in the hardened concrete.
QCS 2014 Section 06: Road Works Page 17
Part 06: Concrete Road Pavements

2 Transverse joint grooves which are initially constructed less than the full width of the slab
shall be completed by sawing through to the edge of the slab and across longitudinal joints as
soon as any forms have been removed and before an induced crack develops at the joint.

3 Sawn transverse joint grooves shall be undertaken as soon as possible after the concrete
has hardened sufficiently to enable a sharp edged groove to be produced without disrupting
the concrete and before random cracks develop in the slab. The grooves shall be between
1/4 and 1/3 of the specified depth of the slab and of any convenient width not less than 3mm.
The sealing groove may be constructed at the same time to be sawn to the required width
later. Unless otherwise approved by the Engineer, expansion joint sealing grooves shall be
sawn immediately before sealing.

4 Construction Joint Grooves in Surface Slabs shall be formed by fixing a groove-former, strip
or cork seal along the top edge of the slab already constructed, before concreting the
adjacent slab. Where the edge of the concrete is damaged it shall be ground or made good
to the approval of the Engineer before fixing the groove forming strip.

5 Alternatively the subsequent slab may be placed adjacent to the first and a sealing groove

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sawn later in the hardened concrete to the minimum depth required in Table 6.3 or to the
manufacturer's instructions if greater, and to sufficient width to eliminate minor spalling of the
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joint arris, up to a maximum of 25mm for longitudinal joints and 40mm for transverse joints.
The joints shall be sealed.
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6.3.17 Groove Formers and Bottom Crack Inducers
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1 Except where joint grooves are sawn, a bottom crack inducer shall be provided at each
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contraction, warping or longitudinal joint position.

2 The bottom crack inducer shall be an approved triangular or inverted Y-shaped fillet, with a
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base width not less than the height, made of timber or rigid synthetic material. It shall be
firmly fixed to the sub-base so as to remain in position during the whole process of
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constructing the slab.

3 The combined depth of groove formers and bottom crack inducers shall be between 1/4 and
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1/3 of the depth of the slab and the difference between the depth of the groove former and
the height of the bottom crack inducer shall not be greater than 20mm.

4 The groove former for wet formed transverse joint grooves shall be made of an approved
rigid material of a width not greater than the required width of sealing groove as in Table 6.3.
The groove former shall be smooth sides with rounded protrusions no greater than 3mm. Any
removable part of the groove former may be tapered with a maximum difference in width of
2mm in 20mm depth.

5 Groove forming sealing strips for wet formed longitudinal joints shall be of firm compressible
strips of ethylene vinyl acetate foam of a minimum density of 90kg/m3, or synthetic rubber, or
equivalent material subject to approval by the Engineer. They shall have a minimum
thickness of 5mm and shall be sufficiently rigid to remain vertical and straight in the concrete
without curving or stretching. They shall be inserted continuously along the joint.

6 For CRCP Universal Beam Anchorage Transverse Joints one side of the beam shall be
separated from the CRCP slab by an expansion joint filler board against the vertical face and
ethylene vinyl acetate foam or similar compressible material, between 5 mm and 10mm thick,
stuck under the top flange.
QCS 2014 Section 06: Road Works Page 18
Part 06: Concrete Road Pavements

6.3.18 Joint Filler Board

1 Joint filler board for expansion joints and manhole and gully slab joint shall be 25mm
thickness unless otherwise shown in the Drawings, within a tolerance of ± 1.5mm.

2 It shall be self expanding cork seal or a firm compressible material or a bonded combination
of compressible and rigid materials of sufficient rigidity to resist deformation during the
passage of the concrete paving plant.

3 The depth of the joint filler board for manhole and gully slabs shall be the full depth of the
slab minus the depth of the sealing groove. In expansion joints, the filler board shall have a
ridged top as shown on the Drawings, except where a sealing groove former is permitted by
the Engineer.

4 Holes for dowel bars shall be accurately bored or punched out to form a sliding fit for the
sheathed dowel bar.

6.3.19 Preparation and Sealing of Joint Grooves

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1 All transverse joints in surface slabs, except for construction joints in CRCP shall be sealed
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using one of the joint seals described. Additionally longitudinal joints which are sawn or
widened shall be sealed.
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2 Joint grooves shall be prepared in accordance with BS 5212: Part 2 and in compliance with
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(a) through (g) below:

(a) that part of the groove former used to form the sealing groove or any temporary seal
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shall be removed cleanly without damaging the joint arises to a minimum depth of
25 mm where compression seals are used or otherwise to such depth as will provide
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an applied seal to the dimensions as will provide in Table 6.3.

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(b) if joint grooves are not initially constructed to provide the minimum dimensions for the
joint seals as given in Table 6.3, they shall be widened by sawing. Joint grooves
formed by tapered formers need not to be widened. The sealing grooves shall be
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cleaned out immediately after sawing using high pressure water jets, to remove all
slurry from the joint, before the slurry hardens.
(c) if rough arrises develop when grooves are made they shall be ground to provide a
chamfer approximately 5mm wide. If the groove is at an angle up to 10 degrees from
the perpendicular to the surface, the overhanging edge of the sealing groove shall be
sawn or ground perpendicular. If spalling occurs or the angle of the former is greater
than 10 degrees the joint sealing groove shall be sawn wider and perpendicular to the
surface to encompass the defects up to a maximum width, including any chamfer, of
40 mm for transverse joints and 25mm for longitudinal joints. If the spalling cannot be
so eliminated then the arris shall be repaired by an approved thin bonded arris repair
using cementitious materials.
(d) for applied sealants the sides of the joint sealing groove shall be scoured by dry
abrasive blasting. This shall not be carried out before the characteristics compressive
2
strength of the concrete is expected to reach 15 N/mm . When compression seals are
used, the sides of the groove may be ground or wire brushed.
QCS 2014 Section 06: Road Works Page 19
Part 06: Concrete Road Pavements

(e) for hot and cold applied sealants, compressible caulking material, debonding strip or
tape or cord compatible with the sealant, of a suitable size to fill the width of the sealing
groove shall be firmly packed or stuck in the bottom of the sealing groove to such a
depth so as to provide the correct depth of seal as described in Table 6.3 with the top
of the seal at the correct depth below the surface of the concrete.
(f) all grooves shall be cleaned of any dirt or loose material by air blasting with filtered, oil
free compressed air. The groove shall be clean and dry at the time of priming and
sealing.
(g) for applied sealants the joint grooves shall be primed with the relevant primer for the
hot or cold applied sealant in accordance with the manufacturer's recommendations
and with BS 5212: Part 2, except that when necessary the joint grooves may be
primed and sealed earlier than 14 days after construction, as soon as the grooves
have been grit-blasted and cleaned.

6.3.20 Sealing with Applied Sealants

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1 Sealing shall be carried out continuously along the full length of joint in any one rip, except for

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remedial areas. When hot or cold applied sealants are used the sealant shall be applied
within the minimum and maximum drying times of the primer recommended by the
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manufacturer. Priming and sealing with applied sealants shall not be carried out when the
naturally occurring temperature in the joint groove to be sealed is below 10 C except
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between 8 C and 10 C it may be carried out when the temperature is rising.
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2 Hot applied sealants shall be heated in and applied from a thermostatically controlled,
indirectly heated dispenser with the recirculating pump. The sealant shall not be heated to a
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temperature higher than the safe heating temperature nor for a period longer than the safe
heating period, both as specified by the manufacturer. The dispenser shall be cleaned out at
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the end of each day and reheated materials shall not be used.

3 The components of cold-applied sealants shall be thoroughly mixed in the correct proportions
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in accordance with the manufacturer's instructions using an automatic metering and mixing
dispenser approved by the Engineer or, for hand application, using a power operated paddle
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mixer for sufficient time to produce homogenous mix without entrapped air. As soon as
possible after mixing and within the worklife of the sealant, the material shall be dispensed
into the joint, or applied using a caulking gun, to the correct level below the concrete surface.
The tack-free time shall be achieved within 3 hours, for machine dispensed material, or within
12 hours for hand applied material.

4 Test certificates shall be supplied from an approved testing laboratory stating that the sealant
complies with the relevant standard. Site testing of cold applied sealants shall be in
accordance with BS 5212: Part 2. Hot-applied sealants shall be sampled at the same rate
and checked for dimensions as in BS 5212: Part 2 and by the penetration test of the relevant
standard for the material.
QCS 2014 Section 06: Road Works Page 20
Part 06: Concrete Road Pavements

Table 6.3
Dimensions of Applied Joint Seals

Type and Minimum Cold Hot Impregnated Depth of Seal

Spacing of Width (mm) Applied Applied Foam Below the
Joints (m) (mm) (mm) Compression Concrete
Strips (mm) Surface(mm)
Contraction:
15 and under 13 (Note 2) 13 15 30 5+2
Over 15 to 20 20 15 20 30 5+2
Over 20 to 25 30 20 25 40 5+2
Expansion All 30 20 25 40 7+2
Transverse 10 10 13 30 5+2
Warping
Longitudinal 10 10 13 30 0 to 5
Joints (if
sealed)

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Gully and 20 15 20 30 0 to 3
Manhole Slabs

Note: (1)
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The depth of seal is that part in contact with the vertical face of the joint groove.
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The depth of seal below the surface shall be taken at the centre of an applied
seal relative to a short straight edge, 150mm long, placed centrally across the
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joint within 7 days of sealing.

Note: (2) For cork seals other than in construction joints, grooves shall be 20 mm wide and
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50 mm deep.
6.3.21 Sealing with Compression Seals
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1 When compression seals are used, the widths of the seal shall be selected in relation to the
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width of the sealing groove, the bay lengths and manufacturer's recommendations so that the
estimated maximum width of the joint opening shall be not more than 70% of the original
width of the seal, the estimated maximum width being calculated on the basis of a movement
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of 4mm per 10m run of slab.

2 The maximum calculated width of sealing groove shall be 30mm.

3 The depth of groove shall be such that the contact face of the seal with the side of the groove
shall be not less than 20mm and that the top of the seal shall be a minimum of 3mm below
the surface of the concrete.

4 Compression seals shall be inserted into the grooves without prior extension or rotation and,
where recommended by the manufacturer, with a lubricant adhesive which is compatible with
the seal and the concrete. The adhesive shall be applied to both sides of the sealing groove
or the seal, or to both. The seal shall be positioned with its axis perpendicular to the concrete
surface. Excess adhesive on top of the seal shall be removed to prevent adhesion of the top
faces of the seal under compression.

5 Except when compression seals are used in longitudinal joints the transverse joint seal shall
be continuous across the slab and the longitudinal joint groove forming strips shall be cut to
the required depth after the concrete has hardened for the transverse seal to be inserted.
QCS 2014 Section 06: Road Works Page 21
Part 06: Concrete Road Pavements

6 If compression seals are used in longitudinal joints where the grooves have been sawn after
construction of the slab they shall be continuous across transverse joints, with the transverse
seals butted and fixed to the longitudinal seals with adhesive.

6.3.22 Joint Seals

1 Joint seals shall consist of hot or cold applied sealants or compression seals or self
expanding cork seals.

2 Hot-applied sealants shall comply with ASTM Standard D3406, or D7116 (for fuel-resistant
sealant).

3 For joints between concrete surface slabs and bituminous surfacing, polymer modified
bitumen sealing strips shall be used and applied in accordance with the manufacturer's
instructions. Hot-applied sealants complying with BS 2499 & BS EN 14188 may be used for
such joints and in joints in asphalt kerbs laid on concrete pavements.

4 Cold applied sealants shall be Type N complying with BS 5212: Part 1 except that Type F

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shall be used for lay-bys and hardstandings.

5
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For joints in kerbs and joints other than in pavements, seals may be any of the pavement
sealants if they have the suitable characteristics for the application. Also, gunning grade cold
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applied plasticised bituminous rubber sealant or gunning grades of two part polysulphid-
based sealants complying with BS EN ISO 11600 may be used.
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6 Alternatively, polyurethane-based sealing compounds may be used provided their

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performance is not inferior to BS EN ISO 11600 material.

7 Compression seals shall be pre-compressed neoprene impregnated expanding foam sealing

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strip, or rubber seals made of polychloroprene elastomers complying with BS 2752 and
conforming to the requirements of ASTM Standard D2628-91.
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8 Compression seals shall be shaped so that they will remain compressed at all times and
shall have a minimum of 20mm contact face with the sides of the sealing groove. If lubricant
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adhesive is used, it shall be compatible with the seal and the concrete and shall be resistant
to abrasion, oxidisation, fuels and salt.

9 Self Expanding Cork seals may be used in longitudinal joints, joints for manhole and gully
slabs and for transverse joints in short lengths of individual slabs or for replaced slabs.

6.3.23 Joints at Manhole and Gully Slabs

1 Manhole covers, gullies and their frames shall be isolated from the pavement slabs and be
contained in separate small slabs, which shall be larger than the exterior of the manhole and
gully shafts, including any concrete surround less than 150mm below the underside of the
sub-base layer. The joint around the manhole or gully slab shall be vertical and incorporate
joint filler board but without dowel bars and tie bars.

2 Gully slabs in unreinforced concrete slabs shall be adjacent to or straddle a transverse joint,
extending the gully slab as necessary to a maximum of 2m. Where this is impractical, an
extra tied warping joint shall be provided adjacent to or within the gully slab and at least 2m
from the next transverse joint. If the edge of an isolator slab is within 1m of any longitudinal
joint the isolator slab shall be extended to that joint.
QCS 2014 Section 06: Road Works Page 22
Part 06: Concrete Road Pavements

3 Manhole slabs in unreinforced concrete slabs shall be adjacent to or straddle transverse or

longitudinal joints. If the manhole is within the middle third of the bay length a warping joint
shall be constructed on one side of the manhole slab across the whole width of the bay to the
nearest longitudinal joint.

4 Reinforcement as shown on the Drawings shall be placed in the main concrete slabs in the
corners between the manhole and gully slab and the transverse or longitudinal joints. Extra
reinforcement as described in the Contract shall be placed in reinforced concrete slabs
around the manhole or gully slabs.

5 Manhole and gully slabs shall have oblique corners, minimum 200mm long, at approximately
45 degrees to the axis of the pavement at all corners which are not adjacent to a transverse
or longitudinal joint in the main slab.

6 Reinforcement as shown on the Drawings shall be placed in the gully or manhole slab and
concrete grade C40 shall be placed by hand in the space between the main slab and the
manhole frame. The concrete shall be fully compacted and finished.

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7 A sealing groove shall be made directly above the joint filler board and sealed.

6.3.24 Inspection of Dowel Bars

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1 The position and alignment of dowel bars at contraction and expansion joints shall be
checked by measurement relative to the side form or guide wires.
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2 When the slab has been constructed, the position and alignment of dowel bars and any filler
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board shall be measured after carefully exposing them across the whole width of the slab.
When the joint is an expansion joint the top of the filler board shall first be exposed
sufficiently in the plastic concrete to permit measurement of any lateral or vertical
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displacement of the board. During the course of normal working these measurements shall
be carried out at a rate of one joint per 1500m length of slab or one per 5 working days
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whichever occurs the sooner. For small areas the rate shall be decided by the Engineer.

3 If the position or alignment of the bars in a single joint in the slab is unsatisfactory then the
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next two joints shall be inspected. If only one joint of the three is defective, the rate of
checking shall be increased to one joint per day until the Engineer is satisfied that
compliance is being achieved. In the event of non-compliance in two or more successive
joints, the Contractor shall revert to the construction of trial lengths and make any necessary
alterations to the concrete mix, paving plant or methods until the dowel bar position and
alignment is satisfactory.

4 After the dowel bars have been examined, the remainder of the concrete shall be removed
500mm on each side of the line of the joint, and reinstated to the satisfaction of the Engineer.
Alternatively if the dowels are examined in the penultimate joint of a day's work that joint shall
be made a construction joint for the next day's work and the remainder of the concrete in the
last slab may be discarded.

6.3.25 Side Forms, Rails and Guide Wires

1 All side forms and rails shall be made of steel and be sufficiently robust and rigid to support
the weight and pressure caused by the paving equipment. Side forms for use with wheeled
paving machines shall incorporate metal rails firmly fixed at a constant height below the top
of the forms.
QCS 2014 Section 06: Road Works Page 23
Part 06: Concrete Road Pavements

2 The forms shall be secured by using not less than three pins for each 3m length having one
pin fixed at each side of every joint. Forms shall be tightly joined together by a locked joint,
free from play or movement in any direction. Forms shall be cleaned and oiled immediately
before each use. The rails or running surface shall be kept clean in front of the wheels of any
paving machine. The forms shall be straight within a tolerance of 3mm in 3m.

3 The forms shall be bedded on low moisture content cement mortar or concrete grade C7.5
and set to the pavement surface level as shown on the Drawings within a tolerance of +3mm.
The bedding shall not extend under the slab. There shall be no vertical step between the end
of adjacent forms greater than 3mm. The horizontal alignment for forms shall be to the
required alignment of the pavement edge as shown on the Drawings within a tolerance of +
10mm. The mortar or concrete bedding shall be broken out after use.

4 Side forms shall not be removed earlier than 6 hours after the completion of the construction
of the slab. Care shall be taken to prevent damage to the concrete and any projecting tie
bars during the removal of the forms. If the removal of forms results in any damage to the
concrete the period of 6 hours shall be increased to that which is necessary to avoid further

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damage and the Contractor shall make good the damaged areas.

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5 Unless otherwise agreed by the Engineer, a guide wire shall be provided along each side of
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the slab to be constructed by slip form paving plant. Each guide wire shall be at a constant
height above and parallel to the required edges of the slab as shown on the Drawings, within
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a vertical tolerance of + 3mm. Additionally one of the wires shall be at a constant horizontal
distance from the required edge of the pavement as shown in the drawings within a lateral
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tolerance of + 10mm.
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6.3.26 Delivery, Storage and Batching of Concreting Materials

1 Aggregate for roadworks shall be delivered to and stored on the Site in one of the following
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ways:
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(a) in separate nominal single sizes of coarse aggregate and fine aggregate.
(b) as graded coarse aggregate of appropriate size and fine aggregate.
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(c) as all-in aggregate for grades C20 to below.

2 If the Contractor proposes to blend aggregate off the site from two separate sources, he shall
obtain the Engineer's approval for the blending process, and for the arrangements for
inspection during the course of the work.

3 Aggregate brought on to the Site shall be kept free from contact with deleterious matter. Fine
aggregate nominally below 5 mm sieve size shall have been deposited at the site for at least
8 hours before use.

4 Batching plant and storage for aggregate shall comply with the following requirements as
appropriate to the method of delivery:

(a) if separate gradings of aggregate are stockpiled, separate accommodation shall

be provided for each nominal size of coarse aggregate or blend of fine
aggregate. The base for stockpiles shall be suitably surfaced to prevent
contamination of the aggregate. Drainage of the stockpile bases shall be
provided.
QCS 2014 Section 06: Road Works Page 24
Part 06: Concrete Road Pavements

(b) aggregate shall be measured by mass and provision shall be made for batching
each nominal size or blend of aggregate separately, to the tolerances specified in
BS EN 206 & BS 8500.
(c) all-in aggregate shall be delivered and stockpiled in such a manner and to a
height that avoids segregation.

6.3.27 Mixing Concrete

1 Mixing concrete shall conform to the requirements of Section 5 Part 7 except as amended
herein.

2 Concrete shall be mixed on site in a stationary batch type mixer in compliance with BS EN
206 & BS 8500 unless with the approval of the Engineer, ready mixed concrete is supplied
from an approved source.

3 The drums or blades of all mixers shall be operated at the speed using for testing, in
accordance with BS 3963 for the mix proportions required, within a tolerance of ± 1 revolution

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per minute. The mixing blades of a pan mixer shall be maintained within the tolerances

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specified by the manufacturers of the mixer and the blades shall be replaced when it is no
longer possible to maintain the tolerances by adjustment. All drums or pans which have
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been out of use for more than 30 minutes shall be thoroughly cleaned before any fresh
concrete is mixed in them.
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4 The rated output of the batching and mixing plant shall exceed by at least a third the amount
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of concrete that is required at a constant rate to enable the paving train to move forward
continuously, at the planned rate of progress.
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6.3.28 Transport and Delivery

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1 Transportation, delivery of concrete shall conform to the requirements of Section 5 Part 8.

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6.3.29 General Requirements for Construction by Machine

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1 The concrete slab shall be constructed in a continuous process by either slip-form or by fixed
form paving plant or by small paving machines or hand guided methods.

2 The slab may be constructed in either one or two layers. In two layer construction the
thickness of the top layer shall be not less than 50mm or twice the maximum size of the
coarse aggregate whichever is greater, and shall be at least 15 mm thick than the depth of
the groove former, if used.

3 While the concrete is still plastic its surface shall be brush-textured and the surface and
edges shall be cured.

4 The spreading, compacting and finishing of the concrete shall be carried out as rapidly as
possible and the paving operation shall be so arranged as to ensure that the time between
the mixing of the first batch of concrete in any transverse section of the slab and the
application of the sprayed curing membrane to the surface of that section shall not exceed
those given in Table 6.4.

5 Each bay in jointed concrete surface slabs shall be consecutively numbered near the verge
next to a transverse joint while the concrete is plastic. In continuously reinforced concrete
pavement the slab shall be marked with the chainage at intervals not greater than 50m apart.
QCS 2014 Section 06: Road Works Page 25
Part 06: Concrete Road Pavements

6.3.30 Construction by Fixed Form Paving Machines

1 A fixed form paving train shall consist of separate, powered machines which spread compact
and finish the concrete in a continuous operation.

2 Concrete shall be discharged without segregation into a hopper spreader which is equipped
with the means of controlling its rate of deposition onto the sub-base or onto the lower layer.
The concrete shall be spread in each layer without segregation and to a uniform
uncompacted density over the whole area of the slab.

3 The deposited concrete shall be struck off to the necessary level by the underside of the
hopper as it is traversed across the spreading machine.

4 The machine shall be capable of being rapidly adjusted for changes in average and
differential surcharge necessitated by changes in slab thickness or crossfall. When the slab
is constructed in two layers, the spreading of the concrete in the top layer shall follow the
completion of the bottom layer within the times given in Table 6.4.

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5 Prior to being compacted, the surface level of each loose spread layer shall be adjusted to
the correct surcharge by means of rotating strike-off blades or a screw device.

6
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The concrete shall be compacted by vibration or by a combination of vibration and
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mechanical tamping throughout the full depth of the slab. Poker vibrators shall be used in
each layer adjacent to the side forms and the edge of a previously constructed slab.
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7 The initial regulation and finish to the surface of the slab shall be effected by means of a
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beam oscillating transversely or obliquely to the longitudinal axis of the pavement. This beam
shall be readily adjustable for both height and tilt.
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8 When grooves are wet-formed the concrete shall be recompacted around the former by a
hand held vibrating plate compactor drawn along or on each side of the joint, prior to
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regulation of the surface by the diagonal finishing beam. Or recompacted and finished if the
former is inserted after the finishing beam.
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9 The regulation and finishing of the surface of the slab shall be carried out by a machine which
incorporates twin oblique oscillating finishing beams which shall be readily adjustable for both
height and tilt. The beams shall weigh not less than 170 kg/m, be of rectangular section and
span the full width of the slab. The leading beam shall be vibrated. The beams shall be
supported on a carriage, the level of which shall be controlled by the average level of not less
than four points evenly spaced over at least 3.5m of the supporting rail, beam or slab, on
each side of the slab that is being constructed. After the final regulation and before texture is
applied any excess concrete on top of the groove former shall be removed.

10 When a concrete slab is constructed in more than one width, flanged wheels on the paving
machines shall not be run directly on the surface of any completed part of the slab. The
second or subsequent slabs shall be constructed either by supporting machines with flanged
wheels on flat bottom section rails weighing not less than 15 kg/m laid on the surface of the
completed slab, or by replacing the flanged wheels on that side of the machines by smooth
flangeless wheel.. Flangeless wheels or rails shall be positioned sufficiently far from the
edge of the slab to avoid damage to that edge.
QCS 2014 Section 06: Road Works Page 26
Part 06: Concrete Road Pavements

6.3.31 Construction by Slip-Form Paving Machine

1 A slip-form paving train shall consist of powered machines which spread, compact and finish
the concrete in a continuous operation.

2 The slip-form paving machine shall compact the concrete by internal vibration and shape it
between sliding side forms or over fixed side forms by means of either a conforming plate or
by vibrating and oscillating finishing beams.

3 The concrete shall be deposited without segregation in front of the slip-form paver across its
whole width and to a height which at all times is in excess of the required surcharge. The
deposited concrete shall be struck off to the necessary average and differential surcharge by
means of a strike-off plate or a screw auger device extending across the whole width of the
slab. The equipment for striking off the concrete shall be capable of being rapidly adjusted
for changes of the average and differential surcharge necessitated by changes in slab
thickness or crossfall.

4 The level of the conforming plate and finishing beams shall be controlled automatically from

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the guide wires by sensors attached at the four corners of the slip form paving machine. The
alignment of the paver shall be controlled automatically from the guide wire by at least one
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sensor attached to the paver. The alignment and level of ancillary machines for finishing,
texturing and curing of the concrete shall be automatically controlled relative to the guide wire
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or to the surface and edge of the slab.
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5 Slip-form paving machines shall have a vibration of variable output, with a maximum energy
output of not less than 2.5 kW per metre width of slab per 300mm depth of slab for a laying
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speed of up to 1.5m per minute or pro rata for higher speeds. The machines shall be of
sufficient mass to provide adequate reaction on the traction units to maintain forward
movements during the placing of concrete in all situations.
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6 Where grooves are wet-formed the concrete shall be compacted around the former by a
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separate vibrating plate compactor with twin plates. The groove former shall be compacted to
the correct level by a vibrating pan which may be included with the transverse joint finishing
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beam. In addition a hand held vibrating float, at least 1m wide, shall be drawn over the
surface along the joint. Alternatively the surface shall be regulated with a longitudinal
oscillating float travelling across the slab. Any excess concrete on top of the groove former
shall be removed before the surface is textured.

7 Where a concrete surface slab is constructed in more than one width or where the edge
needs to be matched for level to another section of surface slab, and the surface levels at the
edges are not achieved, paving shall be carried out over separate fixed side forms to support
the edge to the required levels.

6.3.32 Construction by Small Paving Machines or Hand Guided Methods

1 As an alternative to fixed form or slip-form paving trains, the concrete slab may be
constructed using parts of trains, small paving machines, truss type finishing beams or hand
guided methods. Hand tamping beams may only be used for short lengths or infill bays or
tapers. Reinforcement, dowel bars and tie bars shall be supported in position, except where
two layer construction is used and reinforcement is placed on the bottom layer in a method of
construction approved by the Engineer.
QCS 2014 Section 06: Road Works Page 27
Part 06: Concrete Road Pavements

2 The concrete shall be spread uniformly without segregation or varying degrees of

precompaction, by conveyor, chute, blade or auger. The concrete shall be struck off by a
screed or auger so that the average and differential surcharge is sufficient for the surface of
the slab to be at the correct levels after compaction of the concrete.

3 The concrete shall be compacted by vibrating finishing beams across the slab and with
vibrating pokers adjacent to the side forms or the edge of a previously constructed slab. In
addition, internal poker vibration shall be used for slabs thicker than 200mm and may be
used for lesser thicknesses. When used, the pokers shall be at points not more than 500mm
apart over the whole area of the slab, or drawn continuously across the slab in front of the
finishing beams.

4 The finishing beams shall be metal with a contact face at least 50mm wide. They shall be
rigid or supported by a frame or truss without sag across the width of slab being paved. The
beams shall be supported on rails or forms or an adjacent slab and shall be moved forward
at a steady speed of 0.5m to 2m per minute whilst vibrating, to compact the concrete and to
produce a smooth surface finished to the correct crossfalls, crowns and levels relative to the

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top of the forms or adjacent slab.

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5 Any irregularities at wet-formed joint grooves shall be rectified by means of a vibrating float at
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least 1.0 m wide drawn along the line of the joint. The whole area of the slab shall be
regulated by two passes of a scraping straight edge not less than 1.8m wide or by a further
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application of a twin vibrating finishing beam. All slabs shall be checked for level using a
straight edge at least 4m long. Any excess concrete on top of the groove former shall be
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removed before the surface is textured.

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6 The surface shall be brush textured.

7 The surface shall be cured within the time to completion given in Table 6.4
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Table 6.4
Maximum Working Times
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Reinforced Concrete Slabs

All other Concrete Slabs
Temperature of Consumed in Two layers
concrete at discharge
Mixing first Mixing first
from the delivery between
layer to between layer to
vehicle layers in 2
finishing layers finishing
layer work
concrete concrete

Not more than 25 °C 3 hours 1/2 hour 3 hours 1 1/2 hours

Exceeding 25 °C 2 hours 1/2 hour 2 hours 1 hour

unacceptable
unacceptable
Exceeding 30 °C for paving
for paving
QCS 2014 Section 06: Road Works Page 28
Part 06: Concrete Road Pavements

6.3.33 Surface Textures

1 After the final regulation of the surface of the slab and before the application of the curing
membrane, the surface of concrete slabs to be used as running surfaces shall be brush
textured in a direction at right angles to the longitudinal axis of the carriageway.

2 The texture shall be applied evenly across the slab in one direction by a brush not less than
450 mm wide. The texture shall be uniform both along and across the slab.

3 Curing

4 Immediately after the surface treatment, the surface and exposed edges of surface slabs
shall be cured for a minimum period of 7 days (unless the Engineer agrees to a shorter
period). This will be by the application of an approved resin based aluminised curing
compound, or polythene sheeting or an approved sprayed plastic film which hardens into a
peelable plastic sheet. It shall be removed before road marking and opening to traffic.

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5 Resin based aluminised curing compound shall contain sufficient flake aluminium in finely

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divided dispersion to produce a complete coverage of the sprayed surface with a metallic
finish. The compound shall become stable and impervious to evaporation of water from the
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concrete surface within 560 minutes of application and shall have an efficiency index of 90%
when tested as described in BS 7542.
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6 The curing compound shall not react chemically with the concrete to be cured and shall not
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crack, peel or disintegrate within three weeks after application.

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7 Prior to application, the contents of any containers shall be thoroughly agitated. The curing
compound shall be mechanically applied using a fine spray onto the surface at a rate of at
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least 0.221L/m2. For the sides of slip-formed slabs or when the side forms are removed
within 24 hours and for small areas where mechanical application cannot be used, the
compound shall be sprayed by hand lance at a rate of at least 0.271/m2. The rate of spread
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shall be checked during construction of each trial length and subsequently whenever required
by the Engineer.
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8 The mechanical sprayer shall incorporate an efficient mechanical device for continuous
agitation and mixing of the compound in its container during spraying.

9 Continuously reinforced concrete road bases shall also be cured. Wet lean concrete road
bases and sub-bases shall also be cured.

10 REQUIREMENTS FOR WET LEAN CONCRETE

11 Materials and Mix Designs

12 The constituent materials and the grades of concrete for wet lean mix shall comply with the
requirements of Section 5: Part 16.

13 Placing

14 Wet lean concrete shall be spread uniformly without segregation and without varying degrees
of pre-compaction.
QCS 2014 Section 06: Road Works Page 29
Part 06: Concrete Road Pavements

15 The concrete shall be struck off to a level so that the surcharge is sufficient to ensure that
after compaction the surface is at the required level.

16 Compaction

17 The spread wet lean concrete shall be compacted using internal or external vibration, or
combination of both to meet the required density.

18 Compaction and finishing to level shall be completed within the times given in Table 6.4.

19 Joints

20 At transverse and longitudinal construction joints between two separately constructed slabs,
the previously laid slab end or edge shall present a vertical face before construction of
subsequent slabs.

21 Longitudinal joints in wet lean concrete shall be staggered by at least 300mm from the
position of longitudinal joints in any superimposed concrete slab, and by 1m for transverse

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joints.

6.3.34 Strength
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1 From each sample, three cubes of the appropriate size shall be made, cured and tested in
compliance with BS 1881.
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2 One of each group shall be tested at 7 days and the other two at 28 days. The cubes shall
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be assessed for compliance on groups of four 28-day test results in accordance with BS EN
206 & BS 8500 for compliance with the grade required.
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3 If the average value of any four consecutive results of tests at 7 days falls below the required
values the cement content of the mix shall be increased by an amount agreed with the
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Engineer which shall be maintained until the corresponding 28-day test results have been
assessed.
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6.3.35 Trial Mixes

1 Trial mixes complying with the requirements for pavement quality concrete shall be required
for designed mixes for Grade C15 and above, unless recent data relating to the proposed
mix is approved by the Engineer.

6.3.36 Trial Length

1 At least 10 days before the start of the main wet lean concrete works a trial length of at least
400 m2 for mechanised construction and 30m for hand guided methods shall be constructed.

2 The trial length shall be laid to assess the suitability of the proposed material, plant,
equipment and construction methods to meet the requirements of the Specification.

3 The main construction in the permanent works shall not start until the trial length has been
approved by the Engineer.
QCS 2014 Section 06: Road Works Page 30
Part 06: Concrete Road Pavements

4 If any trial length does not conform to the Specification another trial length shall be
constructed. Trial lengths not complying with the Specification shall be removed unless they
can be rectified to comply with the Specification to the satisfaction of the Engineer.

5 After approval has been given, the material plant, equipment and construction methods shall
not be changed without the approval of the Engineer.

6 Any proposed changes shall entitle the Engineer to require the Contractor to lay a further trial
length to assess the suitability of the proposed changes.

6.3.37 Surface Finish

1 The surface of the wet lean concrete after compaction and finishing and before overlaying
shall be free from ridges, loose material, pot holes, ruts or other defects.

2 The surface texture shall comply with the sub-Clause for pavement quality concrete, Section
5: Part 16.

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6.4 REQUIREMENTS FOR CEMENT BOUND MATERIALS

6.4.1 General Requirements for Cement Bound Materials hl

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1 Cement bound materials shall be made and constructed as described in the following
clauses.
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2 Cement bound materials shall be tested in accordance with this specification for the
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requirements of Table 6.5

3 Cement water and aggregates shall comply with the requirements of the Section 5: Part 16.
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4 Cement for use in all cement bound materials and aggregates for use in CBM3 and CBM4
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shall be delivered and stored in compliance with the requirements of Section 5: Part 16.
Table 6.5
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Cement Bound Materials Field Requirements

Method of Moisture Minimum

Category Mixing Plant
Batching Content Compaction

mix in place or
CBM 1 volume or mass NOTE 1 NOTE 2
mix in the plant
mix in place or
CBM 2 volume or mass NOTE 1 NOTE 2
mix in the plant

CBM 3 mix in the plant mass NOTE 1 NOTE 2

mix in place or
CBM 4 volume or mass NOTE 1 NOTE 2
mix in the plant

NOTE 1 to suit the requirements for strength surface, level regularity and finish
NOTE 2 95% of cube strength
QCS 2014 Section 06: Road Works Page 31
Part 06: Concrete Road Pavements

Table 6.6
Cement Bound Materials Specimen Requirements

Minimum 7 days Cube

Strength
Compressive Strength
Category Curing
Testing Average Individual
(Note1) (Note2)
(MPa) (MPa)

BS 1924 Part 2 1990

CBM 1 BS 1924 Part 2 1990 4.5 2.5
or BS 1881Part 116

BS 1924 Part 2 1990

CBM 2 BS 1924 Part 2 1990 7.0 4.5
or BS 1881 Part 116

CBM 3 BS 1881 Part 111 BS 1881 Part 116 10.0 6.5

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CBM 4 BS 1881 Part 116 15.0 10.0
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NOTE 1 The average strength of 5 cubes shall not be less than the stated figure
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NOTE 2 The strength of any individual cube shall not be less than the stated figure
6.4.2 Batching and Mixing
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1 Batching and mixing shall be carried out in the appropriate manner described in Table 6.5.
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2 Where the mix-in plant method is used and materials are batched by mass, the materials
shall be batched and mixed in compliance with BS EN 206 & BS 8500. Where continuous
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mixers are used and materials are batched by mass, the continuous mixers shall comply and
tested in accordance with BS 3963.
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6.4.3 Transporting

1 Plant-mixed cement bound material shall when mixed be removed at once from the mixer,
transported directly to the point where it is to be laid and protected from the weather both
during transit from the mixer to the laying site and whilst awaiting tipping.

6.4.4 Laying

1 All cement bound material shall be placed and spread evenly in such manner as to prevent
segregation and drying.

2 Spreading shall be undertaken either concurrently with placing or without delay.

3 Road base cement bound material shall be spread using a paving machine or a spreader box
approved by the Engineer and operated with a mechanism which levels off the cement bound
material to an even depth.

4 Cement bound material shall be spread in one layer so that after compaction the total
thickness is as specified.
QCS 2014 Section 06: Road Works Page 32
Part 06: Concrete Road Pavements

5 At longitudinal or transverse construction joints, unless vertical forms are used, the edge of
compacted cement bound material shall be cut back to a vertical face where the correct
thickness of properly compacted cement bound material has been obtained.

6 In the case of cement bound sub bases under a concrete surface slab or continuously
reinforced concrete road base, longitudinal construction joints in the sub-base shall be
staggered by at least 300mm from the position of the longitudinal joints in the concrete
surface slab or continuously reinforced concrete road base, and by 1m for transverse joints.

6.4.5 Compacting

1 Compaction shall be carried out immediately after the cement bound material has been
spread and in such a manner as to prevent segregation.

2 Special care shall be taken to obtain full compaction in the vicinity of both longitudinal and
transverse construction joints.

3 Compaction shall be carried out in compliance with Table 6.5 and be completed within

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2 hours of the addition of the cement. The 2 hours may be varied at the discretion of the
Engineer if the preliminary trial indicates that this is necessary or appropriate. After
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compaction has been completed, compacting equipment shall not bear on cement bound
material for the duration of the curing period.
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4 The surface of any layer of cement bound material shall on completion of compaction and
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immediately before overlaying, be well closed, free from movement under compaction plant
and from ridges, cracks, loose material, pot holes, ruts or other defects. All loose, segregated
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or otherwise defective areas shall be removed to the full thickness of the layer and new
cement bound material laid and compacted.
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6.4.6 Curing
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1 Immediately on completion of compaction, the surface of concrete or wet lean concrete or

cement bound road bases and sub-bases shall be cured for a minimum period of 7 days
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(unless the Engineer agrees to a shorter period) by one of the following methods:

2 Covering with an impermeable sheeting with joints overlapping at least 300 mm and set to
prohibit egress of moisture. The sheeting shall be removed at the end of the curing period.

3 Bituminous spraying which shall only be applied when there is no visible water. When the
cement bound material is likely to be exposed to high temperatures and solar radiation, the
bituminous spray shall be blinded with light coloured material.

4 Spraying with a curing compound.

5 Spraying with an approved plastic film which when hardened shall be removed before
applying any other pavement layer.

6 Whichever method is used, immediately prior to overlaying with any bituminous layer in
cationic bituminous tack coat shall be applied at a rate between 0.351/m2 to 0.551/m2.
QCS 2014 Section 06: Road Works Page 33
Part 06: Concrete Road Pavements

6.4.7 Preliminary Trial

1 At least 10 days before the start of the main cement bound material works a trial area of at
least 400 m2 shall be laid to asses the suitability of the proposed materials, mix proportions,
mixing, laying, compaction plant and construction procedures.

2 When applicable the area shall include one longitudinal and one transverse construction joint.
The location and area of the trial shall be subject to the approval of the Engineer.

3 The rate of testing for the trial area shall not be less than that required in this section of the
specification.

4 The trial area will only be accepted for main construction in the Permanent Works if it
complies with the Specification.

5 The main construction in the Permanent Works shall not start until the trial has been
approved by the Engineer.

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6 After approval has been given, the materials, mix proportions, mixing, laying compaction
plant and construction procedures shall not be changed without the approval of the Engineer
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who may require the Contractor to lay a further trial area to assess the suitability of the
proposed changes.
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6.4.8 Cement Bound Material Category 1 (CBM1)
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1 CBM1 shall be made from material which has a grading finer than the limits of Table 6.7
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2 In addition to the requirements of Table 6.6 the average compressive strength determined
after immersion in water of five test specimens of CBM1 shall not be less than 80% of the
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average compressive strength of five control specimens when subjected to the test
procedure described in BS 1924: Part 2: 1990, clause 4.3.
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3 After the 7 days immersion period the specimens shall not show any signs of cracking or
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swelling.
Table 6.7
Material for CBM1 - Limit of Grading

BS Sieve Size (mm) Percentage by Mass Passing

50 100
37.5 95
20 45
10 35
5 25
0.600 8
0.300 5
0.075 0

NOTE: The particle size distribution shall be determined by the washing and sieving
method of BS812:
QCS 2014 Section 06: Road Works Page 34
Part 06: Concrete Road Pavements

6.4.9 Cement Bound Material Category 2 (CBM2)

1 CMB2 shall be made from gravel sand, a washed or processed granular material, crushed
rock, all in aggregate, blastfurnace slag or any combination of these. The material shall fall
within the grading limits of Table 6.8.

2 The material shall have 10 % fines value of 50 kN or more when tested in accordance with
BS 812 with samples in a soaked condition.

3 In addition to the requirements of Table 6.6 the average compressive strength determined
after immersion in water of five test specimens of CBM2 shall not be less than 80% of the
average compressive strength of five control specimens when subjected to the test
procedure described in BS 1924: Part 2: 1990, clause 4.3. After the 7 days immersion period
the specimen shall not show any signs of cracking or swelling.

Table 6.8
Material For CBM2 - Range Of Grading

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BS Sieve Size Percentage by Mass Passing
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50 100
37.5 95-100
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20 45-100
10 35-100
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5 25-100
2.36 15-90
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0.600 8-65
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0.300 5-40
0.075 0-10
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NOTE: The particle size distribution shall be determined by the washing and sieving
method of BS 812.
6.4.10 Cement Bound Material Category 3 (CBM3)

1 CBM3 shall be made from aggregates as in the sub-Clause 6.5.9.

2 The grading of the aggregate shall be within the limits of Table 6.9.

6.4.11 Cement Bound Material Category 4 (CBM4)

1 CBM4 shall be made from aggregates as in sub-Clause 6.5.9

2 The grading of the aggregate shall be within the limits of Table 6.9.
QCS 2014 Section 06: Road Works Page 35
Part 06: Concrete Road Pavements

Table 6.9
Material for CBM3 and CBM4 - Range of Grading

Percentage by Mass Passing.

BS Sieve Size (mm)
Nominal Maximum Size

40 mm 20 mm
50 100 -
37.5 95-100 100
20 45-80 95-100
5 25-5- 35-55
0.600 8-30 10-35
0.150 0.8* 0-8*
0.075 0.5 0-5

NOTE: The particle size distribution shall be determined by the washing and sieving

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method of BS 812.
*0-10 for crushed rock fines
6.4.12 Testing of Cement Bound Materials hl
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1 Samples shall be provided in accordance with BS 1924: Part 1: 1990 Clause 5 from the laid
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cement bound material before compaction. One group of five samples shall be provided from
five locations equally spaced along a diagonal that bisects each 800 mm2 or part thereof laid
each day. The number of groups may be increased if required by the Engineer.
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2 One 150 mm cube shall be made from each sample taken in accordance with sub-clause 1
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of this clause. The cubes shall be made in accordance with BS 1924: Part 2: 1990, clause
4.2.5 without further mixing of the material and within 2 hours of the addition of the cement.
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Cubes shall be cured and tested in accordance with Table 6.6.

3 To determine the wet density of cubes the mould shall be weighed prior to making the cube
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and the mass recorded. Immediately after completion of compaction, the cube and mould
shall be weighed and the mass recorded. These masses together with the nominal volume of
the mould shall be used to derive the wet density of the cube.

4 The in-situ wet density of a layer of cement bound material shall be taken as the average of
the wet densities at five locations equally spaced along a diagonal that bisects each 800 m2
or part thereof laid each day. The wet density at each location shall be the average of two
readings obtained using a nuclear density gauge complying with BS 1377: Part 9. The two
readings shall be taken at 180 degrees to each other using the same source rod hole. The
source rod shall be lowered to within 25mm of the bottom surface of the layer. Readings
shall be taken within two hours of completing final compaction.

6.4.13 Special Requirements for Cement Bound Materials

1 Where specified in the contract documents or on the project drawings cement bound road
base in flexible composite construction shall be laid in individual widths with longitudinal
construction joints in locations as detailed below:

(a) Single All purpose. One longitudinal construction joint at the centre lane line marking.
QCS 2014 Section 06: Road Works Page 36
Part 06: Concrete Road Pavements

(b) Dual 2 lane All-purpose. One longitudinal construction joint at the lane line marking.
(c) Dual 3 lane All-purpose. Two longitudinal construction joints, one at each of the lane
line markings.
(d) Dual 2 lane Motorway. Two longitudinal construction joints, one at the lane line
marking and one at the edge line marking between hard shoulder and left hand
lane.
(e) Dual 3 lane Motorway. Three longitudinal construction joints, one at each lane line
marking and one at the edge line markings between hard shoulder and left hand lane.
(f) Dual 4 lane Motorway. Four longitudinal construction joints, one at each lane line
marking and one at the edge line marking between hard shoulder and left hand lane.

2 Longitudinal constructions joints shall not be more than 150 mm from the centre of the centre
line, lane line, or edge line marking, with individual widths not exceeding 4.75 m.

3 Longitudinal construction joints shall not be located within the left hand lane or dual

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carriageways. At tapers and other changes in section the construction joint layout shall be

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agreed with the Engineer, and where necessary joints shall also be permitted within 150 mm
of the mid-point of the traffic lane.
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END OF PART
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